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Patented Aug. 2, I898.

B. HOFFMANN. TELEGBAPHIC TRANSMITTING AND RECEIVING APPARATUS.

(Application filed May 5, 1897.)

4 Sheets-Sheet I.

(No Model.)

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Patented Aug. 2, I898.

B. HUFFMANN, TELEGRAPHIC TRANSMITTING AND RECEIVING APPARATUS.

(Application filed May 5, 1897.)

4 SheetsSheet 2.

(No Model.)

m: NORRIS PETERi c9, WOTDLITHOJWASHINGTON. n. c,

No. 608,333. Patented Aug. 2, I898.

I B. HOFFMANN. TELEGRAPHIC"TRANSMITTING AND RECEIVING APPARATUS.

(Application filed May 5 1897.)

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Patented Aug. 2, I898.

B. HOFFMANN. TE-LEGRAPI-IIG TRANSMITTING AND RECEIVING APPARATUS.

(Application filed May a. 11391.)

4 Sheets-Sheet 4.

(No Model.)

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, UNITED STAT-ES PATENT Y ()FFICE.

BERNHARD HOFFMAN N, OF PARIS, FRANCE, ASSIGNOR TO SOCIETE THEINTERNATIONAL TELESORIPTOR SYNDIOAT, LIMITED, OF LONDON,

ENGLAND.

TELEGRAPHiC'T RANSMI iING AND RECEIVING APPARATUS.

SPECIFICATION forming part of Letters Patent No. 608,333, dated August2, 1898. Application fil d May 5, 1897. Serial No. 635,107. (No model.)Patented iu Luxemburg March 20, 1897, No. 2,789.

To all whom it may concern:

Be it known that L'BERNHARD HOFFMANN, a subject of the Emperor ofAustria-Hungary, residing in Paris, France, have invented certain newand useful Improvements in Telegraphic Transmitting and ReceivingApparatus, (the same being the subject of Letters Patent in LuXemburg,No. 2,7 89, dated March 20, 1897,) of which the following is'aspecification. A

This invention has reference to telegraphic transmitting and receivingapparatus, and has for its object to simplify and improve theconstruction and operation of apparatus of the'character described in myUnited States Letters Patent No. 574,994, of January 12, 1897. Thisobject is attained by the improved and modified apparatus hereinafter described, which will be fully understood from the following descriptionand from the annexed drawings, in which-.

Figure 1 is a diagram showing two apparatus connected up, the one beingin the transmitting position and the other operating as a receiver.Fig. 2 is a front elevation, Fig. 3 a plan, and Fig. 4 a side View, ofan apparatus constructed according to the present invention. The otherfigures show details. Fig. 5 is aface view of the commutator. Figs. 6and 7 are face and edge views of the'typewheel. Fig. 8 is a detail ofthe impressionroller. Fig. 9 is a detail of the circuit-closer for theprinting-magnet. 'Fig. 10 is a diagram. Fig. 11 is a diagram showing the10- cal circuits simplified to make clear the means for synchronizing.

Upon the spindle A, which is driven by a clockwork-movement, is a wheelB, which I will call the type-wheel and which carries on its peripherythe different signs or characters to be transmitted. On the same spindleis mounted an escapement-wheel 0, allowing of the intermittent rotationof a clockworkmovement which drives this spindle. An arm D, carrying twometallic brushes a and b, is mounted on the opposite end of, the spindleA to that which carries the wheel 13 and rotates with an intermittentmovement in front of a commutator or distributing-crown E.

F, interrupted at c, the purpose of which will be explained later.

. The brush a in its rotation rubs successively over a series of sectors10 a: y z, &c., twenty-eight of which are shown in the drawings, Fig. 5,these being normally insulated from each other and respectivelyconnected with the keys of the keyboard of the machine.

The brushes a and b are respectively connected to the rubbers cl and e,which bear upon insulated collars, to which they transmit the current.

The keys of the machine are alternately in communication with one of thepoles of the line-battery H by springs r r r 1, &c., or insulated fromthat pole by the springs r 7' 1. Upon depressing one of the keys incommunication with the battery this latter is cut out of the circuit,because the corresponding contact-springs are thereby caused to pressagainst an insulated portion of the key. On the other hand, bydepressing oneof the insulated keys the battery is placed incommunication with the line.

The movement of the wheel 0 is controlled by any suitable escapement f.In Fig. 1 of the drawings it is shown as a double-pallet escapement. Theescapement f is carried by the armature g of an electromagnet h, thesolenoids of which are arranged to act independently of one another andto attract the armature 9 either to the right or to the left.

. The armature is polarized, and in order that it may be attracted tothe one side or the other it is necessary to develop in the solenoidsopposite polarities to those of the said armature. NVhen the coils ofthis electromagnet are alternately traversed by a current,theescapement-pallet oscillates between the escapement-teeth, and the wheel0 escapes one tooth at each movement, and the brush a then turns to theextent of one division of the commutator E.

There is a relay-electromagnet k, the ob ject of which is to sendcurrents alternately into each of the coils of the electromagnet h. Forthis purpose the armature of the relay 7c is connected with the one poleof a local battery I, while the other pole of this battery is connectedto earth. The two contacts 1 m between which this armature moves areconnected, respectively, to the two coils of 7t. The spindle A alsocarries a wheel J, provided with curved teeth, say twenty-eight innumber, this number being equal to that of the contacts of thecommutator E. Above this wheel is a spring 02, carryinga finger 0, whichis lifted each time a tooth of the wheel J passes beneath it. Thisspring nis connected at one end to the local battery I and carries atits other extremity a pin which may be in communication with a contactconnected to the printirig-electromagnet K. Every time the linger 0falls into a gap of the wheel J the current from the local battery isclosed in the electromagnet K; butby reason of the rapidity of theoperation of the apparatus the spring is thrust back and the contact isonly established for a period which is too limited to allow theelectromagnet K to act. Practically this spring rarely touches itsbearing. It is only when a character is printed and the apparatus stopsthat the linger 0 can enter sufficiently into the gap of the wheel J andthe duration of contact becomes sufllcent to allow the eleetromagnetK tooperate. The apparatus also comprises two commutator keys or switches Land l\[ and a button 0 of a pole ehanger, these being situated above thekeyboard and acting upon springs in order to effect the differentcommunications between the parts of the machine and between theapparatus which are in communication with each other by the line.

In the following (lescription it is supposed, as an example,that theapparatus is combined with a telephone branched on the same line whenthe keys L and M are raised. This telephone is in communication with theapparatus by the terminals t t.

Referring to the scheme of Fig. 1, in which apparatus No. 1 is in thetransmitting position and No. 2 in the receiving position, the path ofthe currents will be as follows: The current passes over the lead 1 tothe springs 2 and 3 of the button 0, the wire 4, the springs W, forexample,wire 5, contact 1 brush a, rubber (1, wire (5, springs '7 and 8of key M, wire 9, electromagnet in, wire 10, springs 11 and 12 of keyM,connection 13, springs ll and 15 of key L,wire l6, and terminal 1 7 ofthe line-wire. At the receivingstation No. 2, the key I. being alonedepressed, the current arrives by the terminal 18, wire 19, springs and21 of key L, connection 22, springs 23 and 2t of M, wire 25,relay-electromagnet 7;,wire 26, springs 27 and 28 of M, wire 2.), andterminal 30, connected to a second line leading to terminal 31 of thetransmitting apparatus or preferably to earth, this latter terminalbeing then situated at earth. In each of the two stations the armatureof the electromagnet 7.", is attraeted, its lever comes into contactwith one of the two contacts Z or m, closes the local circuit by 32, 33,Z, or m, electromagnet 71.,wires 34', springs 35 and 36 of key Ii, wire87, armature of electromagnet a, wire 38, and returns to the battery Iby the terminal 39. The armature g of electromagnet 7t being attractedcauses the eseapement pallets to move, the ratchet-wheel U escapes onetooth, and the brush moves forward upon the commutator E. The followingsector .2', for example, being insulated, the line-current isinterrupted, the electromagnet K allows its armature to return to rest,the local circuit is closed through the second solenoid of 71 thearmature g is attracted in the opposite direction, and the eseapementoperates afresh. There has thus been obtained at the two stations asynchronous forward movement of the brushes (t, and consequently ofthetypewheels 13.

Suppose now that the brush a, leaving a a sector in connection with theline-battery ll, comes upon the following sector, which, instead ofbeing insulated, is also put in communication with the battery by thedepression of the key which corresponds with it on the manipulatingkeyboard. The armature 7.: remains attracted, the local current passesinto the same coil of 7b as at the previous moment, and the eseapementceases to act, and the mechanism stops. The same things occur inidentically the same way if the brush a, leaving an insulated sector,comes upon the following one, which has just been insulated bydepressing the corresponding key. The armature of 7; not being attractedat this moment remains at rest and sends, as at the preceding instant, alocal current into the same coil of 71,. The eseapement no longer acts.At this moment the spring it bears upon the eontaetp, because the linger0 en ters into the gap of the wheel J, which has followed the movementof the brush a. A local current passes through I32, 40, n, p, and ll andelectromagnet K and returns to the battery by Ill, 35, 3 37, 38, and239. The electromagnet K attracts its armature and brings the roller (1and the paper which it carries in contact with the type-wheel. Theprinting is effected at this moment and the character corresponding tothe key depressed appears on the paper. The current coming from theearth terminal ill follows the lead 4-2 through the springs l and ll ofthe polechanging button 0, the wires t5, and the second terminal of theline-battery, completing the circuit. If the button is depressed, thecurrent coming from the terminal 1 passes through the springs -l;7 andel l, then returns by -12 to the terminal 31 of the line. The current isthus reversed by this operation. This reversal of current is utilized toobtain synchronous starting of the two apparatus at the commencement ofa communication or even in the course of same. For this purpose therelay n is polarized. Its armature, connected with the electromagnet 7L,as already explained, carries a eontactpieee, by means of which it isfurther put into communication with the local battery I either by thewire 38 and terminalv 30 or by the wire -18 and the contacts betweenwhich it vibrates.

brush at. through the one or the other of the There is a branch wire 49from wire 38, which establishes communication between the latter and thecontinuous portion of the contactring F, and the contact of this latteris in sulated. So long as the current flows in the normal directionthatis to say, so long as the button 0 is raisedthe armature of the IOvwhich connects h with the local battery; but

as soon as the currentis reversed by the depressionof the button 0, asbefore explained,

the armature of n comes against the other contact and puts it incommunication by 48 withthe rubber d. The current returns by the latterthrough I), F, 49, 38, and 39 to the local battery. When in consequenceof the rotation the brush comes upon the contact 0, which is insulated,as above stated, the current from the local battery is cut off from theelectromagnet h, which ceases to act, and the whole arrangement stops inthis position.

To send a call, the bell-call button of the telephone is pressed, thekeys L, M, and O of all the stations being raised.

Totransmit, the transmitting-station depresses L and M, and to receivethe receivingstation depresses L only, as seen in Fig. 1. In thisposition the transmitting-station by depressing the key 0 sends acurrent of reverse direction to the normal into the two apparatus inorder to establish their synchronism.

Suppose the receiving-station to be in advance of thetransmitting-station. The apparatus work together until at thereceivingstation the brush b comes upon 0. At this moment the wholearrangement at the receiving-station stops, and the transmittingstationcontinues to work until its own brush 1) also comes upon its sector 0.Pressure is then removed from the key 0, and the two apparatus worksynchronously together. If, on the contrary, it is thetransmitting-station which is in advance of the other, the two apparatusstop when the brush 1) comes upon the insulated sector 0 at thetransmitting-Sta tion, since it is the latter which produces theemissions and interruptions of the line-current. It is then onlynecessary to lift for an instant the key 0. The two apparatus have thenadvanced togetherto the extent of one contact; but it is now thereceiver which is in advance of the transmitter. Byat once depressingthe key 0 the apparatus are again set in operation, and the case is thesame as the precedingthe receiver stops first. It

is therefore desirable before commencing to transmit to press twiceuponthe button 0 to insure the synchronous starting of the two apparatus.

The parts of the apparatus shown in Fig. 1 are indicated by the sameletters of reference in Figs. 2, 3, 4, and 5, Fig. 5 showing thedistributing ring or commutator.

,I will now proceed to describe certain .details of construction.

It has been seen that the type-wheel is arranged to rotate byintermittent movements each of one twenty-eighth of a revolution. Inorder to increase the facility of. working the apparatus, this wheel isadapted to print a number of characters twice as great as the number ofcontacts of the commutator E. For this purpose the characters or signsengraved on this wheel are arranged in two series alternated in one rowperipherally of the wheel-for example, in the following order: A'l B 2 O3, 8.70. The type-wheel turning one twenty-eighth of a revolution ateach movement of the brush a, the characters are presented in the orderA B O D 1 2 3 4, according to the position of this wheel with respect toits axisthat is to say, that in order. to producethe one or the other ofthese two series it is necessary to turn the wheel forward or backwardone fifty-sixth of a revolution with respect to its spindle. Thearrangement which is employed for this purpose is represented on alarger scale in rear elevation, Fig. 6, and in side view, Fig. 7. Theletters of the alphabet, alternated with the figures and the signs ofpunctuation or expression, are engraved upon the peripheryof the disk13. There are in all fifty-six divisions, fifty-two of which areallotted to the letters, figures, and signs and the four others to thespaces for the letters and to the spaces for the figures. The same keyof the keyboard therefore allows of printing two differentcharacters,according to the position of the disk. Behind the disk 13 and loose onthe spindle A are arranged two arms 0' 8, each formed with a hole to anda beveled nose 0'' 8. Above these arms are springs r 3 each carrying apin r 5 The two arms 1" s are at-any suitable angle to each other, thisbeing determined by the position on the disk of the blank spaces for theletters and for the figures. The angle of r s differs from that of r sby one fifty-sixth of a revolution, in such a manner that never morethan one of the pins 1' 5- may take into the corresponding hole. Thesprings r s have beveled pieces 1" 3 A piece v, having a bevel. o and anangular nose 12 is fixed behind the lever which carries theprinting-roller q. When the key which corresponds on the keyboard to oneof the spaces is depressed, the printing-lever rises, the bevel 'v liftsthe spring 0" or s which is opposite it and disengages the correspondingpin. At the moment this pin is disengaged-the nose 1: strikes the.

extremity of r or s, whichever is opposite it, and causes this to bedeflected and to carry with it the disk B to the extent of onefiftysixth of a revolution. On the otherhand, the

spring, being fixed on spindle A, remains in place, and the second pin1' or s enters into its hole, thus firmly securing the spring, andconsequently the spindle, with the disk B. Thepaper P from an ordinaryreel passes.

over a roller q, provided at its circumference with fine sharp teeth. Aspring-fork r, Fig. 8, presses the ribbon of paper upon the roller,space being left between the forks of the spring for the periphery ofthe type-wheel. The forward movement of the paper is effected asfollows: A ratchet-wheel R is sccured on the roller q, a pawl Sbein gsecured on one of the plates of the casing of the apparatus and gearingwith the ratchet-wheel. \Vhen the printing-electromagnet operates, thearm which carries the roller q rises, the pawl rides over theratchet-wheel R, and the impression is produced. Vhen the current ceasesin the clectromagnet K, its lever returns to its original position, andthe pawl being in gear with its ratchet-wheel causes it to rotate withthe roller q, and consequently moves the paper forward a distancedetermined by the construction of the apparatus.

Fig. 9 represents in elevation the wheel .l with curved teeth, providedwith its spring a and finger 0. The current from the local batteryarrives at the base of the spring at 40, Fig. 1. It passes to theprinting-electromagiiet by the CO11t-{tCii]l,Wl10ll the finger 0 enterscompletely into a gap between two teeth of the wheel J.

It has been before explained that in order to establish synchronism withcertainty between the two apparatus it suffices to twice depress thenormal-current-reversing button 0; but the second depression of thisbutton should be effected immediately it has been allowed to rise, andthis is extremelydifficult in viewof the rapidity of rotation of thebrush a. To obviate this difiieulty, there is arranged a small accessorypart which allows of stopping the apparatus at synchronism without beinglimited by a shorter or longer interval between the two manipulations ofthe button 0. This arrangement is shown separately in Fig. 10.

Upon the spindle A of the type-wheel is fixed acam T,whieh at eachrevolution causes rotation of a star-wheel U to the extent of one teeth.This star-wheel carries a drum V, divided into an even number ofalternately conducting and insulated sectors. The conducting-sectors arein electrical connection with each other. Two springs X X bear upon thesurface of the drum V at two diametrically opposite points in suchmanner that they are in electrical connection with each other when theybear upon metallic sectors of the drum. One of these springs X is inelectrical communication with the sector 0 of the synchronizingcommutator or crown, the other with a spring Y of the button 0, which inthis case is provided with a metallic contact-piece at its lower part.(See Fig. 11.) Another spring Z of the button 0 is in electricalcommunication with the full part F of the synchronizing-ring. lVhen thebutton 0 is up, the contact 0 remains insulated, as in Fig. 1, but whenthe button is depressed the contact ceases to be insulated. \Vhen thetwo springs X and X bear upon metallic sectors of the drum V, being thenconnected to the ring F by wires 90 91 92, Fig. 11, at the nextrevolution of the spindle A, and therefore of the cam T, the contact 0will be insulated, because the two springs X and X bear upon insulatingportions of V. It is only at this moment that the transmitter stops. Atthe receiving-station, the button 0 not being depressed, all takes placeas if the star-wheel and its accessory parts did not exist. lly means ofthis arrangement synchronism will only be effected at thetransmitting-station once in two revolutions, while at thereceiving-station it is enabled tobe effected at every revolution. Thereceiving apparatus will await the stoppage of the transmitter, so thatthe two apparatus may reeommence working together.

As the printing-elcctromagnetdoes not operate when pressure is appliedto 0, it is possible to bring the apparatus to synchronism at any time,even in the middle of a word.

\Vhenever a transmission is finished, it is desirable to twice establishsynchronism, keeping the button 0 depressed, (to prevent the restartingof the apparatus.) Vhen the apparatus stops for the second time and itis desired to leave it in the receiving position, the lever BI islifted. If it be desired to substitute the telephone for the telegraphicapparatus, the two levers are lifted. In the latter case the localbattery is cutout. No part of the apparatus works.

I claim as my invention 1. In a printing-telegraph comprising anescapement mechanism controlled by an electromagnet, circuit-closingmeans for alternately closing and breaking a circuit to operate suchmagnet and escapement, transmitting-keys, and a line-battery, means forsynchronizing the transmitting and receiving instruments consisting of apole-changer for reversing the current of said line-battery, polarizedmagnets or relays at both stations, a local circuit at each instrumentcontrolled by said polarized relay, and means for breaking the localcircuit to stop the instruments, consisting of a revolving brush andsector, included in said local circuit, the sector having a break at thesynchronizing or starting position adapted when the brush reaches saidbreak to open said circuit, substantially as set forth.

2. In a printing telegraph comprising a commutator having segmentsconnected to keys which are alternately grounded and open-circuited, andeach adapted to establish the reverse position when depressed, arevolving brush traversing said segments, a polarized electromagnet, anda connection from said brush normally through said polarized magnet toline, the improved synchronizing means consisting of a pole-changer forreversing the current from the line-battery, and a local circuit dividedinto two branches controlled respectively by said polarized magnet, oneof said branches closed with a current of trolled by an electromagnet inconnection .tion, substantially as hereinbefore set forth.

normal direction, and the other closed when the current is reversed,with a commutator brush and sector connected in the latter branch, andthe sector having a break correspondin g to the synchronizingposition,whereby when the current is reversed on reaching thesynchronizing position, the local circuit is broken, and the instrumentstops until by the manipulation of said pole-changer the current ofnormal direction is restored, substantially as set forth.

3. In a printing-telegraph, the combination with transmitting andreceiving instruments having rotary spindles turning in unison, of apole-changer at the transmitting station and a polarized magnet inconnection with each instrument and means controlled thereby. forstopping the instruments at a. given point in the rotation of theirspindles when the normal current is reversed to enable synchronism to beeffected, of means for suppressing such stoppage except at widerintervals than once to each revolution, comprising a short circuit inconnection with the synchronizing circuit, a circuit-breaker in saidshort circuit, and means for operating said circuit-breaker geared tothe printing'instrument at such ratio of speed as to establish thesynchronizing condition of said circuit at intervals less frequent thanonce to each revolu- 4. In a printing-telegraph comprising transmittingand receiving instruments each having a type wheel rotatedintermittently through an escapement, which in turn is conwith aline-circuit, a synchronizing means consisting of a pole-changer forreversing the direction of the current from the line-battery, apolarized magnet at each instrument, a local circuit operating theescapement magnet thereof, and divided into branches controlled by saidpolarized magnet, a revolving brush and sector included in asynchronizing branch of said circuit, said sector interrupted by aninsulated segment at the synchronizing position for breaking saidcircuit and stopping the instrument, and means for connecting saidinsulated segment in saidbranch circuit except at predeterminedintervals, substantially in the manner set forth.

5. In a printing-telegraph instrument, the type-wheel of which carries adouble series of characters disposed in alternate order around itsperiphery, and capable of displacement upon its spindle to an extentequal to half the advance of the spindle at each movement, mechanism forshifting and locking the typewheel, consisting of the combination withthe type-wheel and spindle of two spring-catches adapted to lock thetype-wheel and spindle together, in their two respectivepositions,

the type-wheelformed with engaging surgages and again locks thetype-wheel and spindle together.

6. In aprinting-telegraph instrument, the type-wheel of which carries adouble series of characters disposed in alternate order around itsperiphery, and capable of displacement upon its spindle to an extentequal to half the advance of the spindle at each movement, mechanism forshifting and locking the typewheel, consisting of the combination withthe type-wheel and spindle of two 'sprin g-catches adapted to lock thetype-wheel and spindle together, in their two respective positions,inclines carried on the type-wheel in two positions corresponding toshifting blanks or spaces, and the printing-lever having a bevel adaptedin either of said positions to disengage the spring-catch, therebyunlocking the type-wheel, and having a noseadapted thereupon to engagethe inclines upon the typewheel and turn the latter to its otherposition, whereupon the other spring-catch engages and again locks thetype-wheel and spindle together, substantially as l1 ereinbe-' fore setforth.

7. In a printing-telegraph instrument the type-wheel of which carries adouble series of characters disposed in alternate order around itsperiphery, and capable of displacement upon its spindle to an extentequal to half the advance of the spindle at. each movement, mechanismfor shifting and locking thetypewheel consisting of the combination withthe type-wheel and spindle, of a spring-catch consisting of a springattached to the spindle and 'movable'in direction perpendicular to thetype-wheel in looking or. unlocking, an incline carried on thetype-wheel inra shifting position, and the printing-lever having a beveladapted in said shifting position to displace said spring-catch, andhaving a nose adapted thereupon to engage the incline upon thetype-wheel and displace the latter, substantially as hereinbefore setforth.

In witness whereof I have hereunto signed my. name in the presence oftwo subscribing witnesses.

'BERNHARD HOFFMANN.

WVitnesses:

EDWARD P. MACLEAN, AUGUSTE MATHIEU.

